Lock

ABSTRACT

A lock including a lock casing (1), a locking mechanism (2) dislaceable therein and connected to a latch bolt (2a) and block means (12), which are movable transversally to the displacement direction of the locking mechanism and resiliently loaded (14) towards positions blocking the locking mechanism, wherein the blocking means can be brought to releasing positions by insertion of a card (3) serving as a key and having recesses (3a) corresponding to the blocking means. The blocking means (12) are preferably annular and entirely guided in the displaceable locking mechanism (2) as well as moveable between two blocking end positions, in which each blocking means is in locking engagement with the lock casing (1a,1b). The card (3) belonging to the lock has through-going, elongated slits (3a) located and dimensioned to receive the annular blocking means (12), so that upon insertion of the card all the blocking means (12) are brought to intermediate positions permitting the displacement of the locking mechanism.

The invention relates to a lock of the kind stated in the preamble ofclaim 1, i.e. a lock which is operable by means of a punched cardserving as a key.

In a lock of this kind known from the Swedish patent specification No.365 572, the blocking means are formed as pins and are actuated bycontrol pins with pointed ends, which fit into corresponding recesses orblind holes in the key card.

To enable a large amount of combinations the key card must have acertain thickness, so that the blind holes can be made of differentdepths and, moreover, a bevel serving as a cam is needed to lift thecontrol pins when the card is inserted. Therefore, the latter must bemade of a hard and wear-resistant material, such as steel, and beproduced with great precision.

The object of the invention is to achieve a lock of the above kind, suchthat the wear of the key card is reduced to a minimum when the same isinserted into the lock. Furthermore, the card should be made as thin aspossible and, in spite thereof, it should permit a large number oflocking combinations and preferably be made of plastic material.

As appears from claim 1, the lock according to the invention has thefeatures that each blocking means comprises a substantially arcuateportion, whereas the card of the lock has through-going slits locatedand dimensioned to receive the arcuate portions of the blocking means.It is hereby achieved that upon inserting the punched card, the arcuateportions of the spring-loaded blocking means can easily slide or roll uponto the card, i.e. with negligible friction, and thereafter be presseddown by their springs into the corresponding, through-going slits of thecard, so that all of the blocking means are brought into releasingpositions. Of course, the blocking means should be mounted in such a waythat they block even during the insertion of the card and, likewise, ifa similar, but false key card or another object is inserted into thelock.

In a preferred embodiment, the blocking means are circular, inparticular annular, and are guided by slits in mutually parallel platesbeing connected at some distance to each other and forming together alocking mechanism which is displaceable in a lock casing. When insertingthe punched card transversally to the displacement direction of thelocking mechanism and in parallel to the plane of the circular, annularblocking means, these blocking means will roll up onto the card and beresiliently pressed down into the slits of the punched card, whereby theblocking means take well-defined positions being free from lockingtongues in the upper and lower parts of the lock casing. The springs ofthe blocking means, especially helical springs, are preferably guidedwithin sleeves, which are arranged inside each circular ring and haverecesses in their upper and lower parts so as to permit the rings toperform a rather large motion upwards and downwards.

The invention will be described further below the reference to thedrawings, which illustrate a preferred embodiment of the lock accordingto the invention.

FIG. 1 is a perspective view of a lock according to the invention and acorresponding punched card key;

FIG. 2 is a side view of the lock, partly in axial section;

FIG. 3 is an exploded view of the different portions of a lockingmechanism; and

FIGS. 4a-c are cross-sectional views of the lock in a "lower lockingposition", an "upper locking position", and a "central releasingposition", respectively.

FIG. 1 illustrates the box-shaped casing 1 of the lock which is suitablymade of metal sheet and comprises locking tongues, 1a,1b punched intothe upper and lower parts thereof, said locking tongues co-operatingwith an internal locking mechanism 2. The latter is connected to a bolt2a protruding through an opening in the front end 1c of the lock casingand to a lock grip 2b protruding transversally from one side of the lockcasing, said grip having an insertion opening 2c for receiving a punchedcard 3 serving as a key.

As appears from FIG. 2, the locking mechanism 2 is linearly displaceablein the lock casing 1 while being guided by opposite profile elements 1d,1e, which are formed by bending the longer walls of the lock casing.Upon insertion of the card 3 into the insertion opening 2c, the lockgrip 2b can be gripped by hand, and the locking mechanism 2 can bedisplaced at will in the lock casing, so that the bolt 2a performs acorresponding displacement movement.

In FIG. 2 the locking mechanism 2 is shown in assembled condition.However, the different parts thereof appear more clearly from FIG. 3,where the parts are dismounted. Thus, the locking mechanism 2 comprisesthree parallel plates, namely an upper plate 4, a middle plate 5, and alower plate 6. These three plates 4,5,6 are held together by means offour screws 7, though at a certain distance from each other by means offour distance sleeves 8 between the upper plate 4 and the middle plate 5as well as two lock grip holders 9 between the middle plate 5 and thelower plate 6. The distance sleeves 8 are fastened to the upper side ofthe upper plate 4 and internally threaded to receive the screws 7.Around each distance sleeve 8 a roller 10 is rotatably mounted, andthese rollers are in rolling engagement with the profile elements 1d, 1eof the lock casing so as to provide the above-mentioned guidance of thelocking mechanism. The lock grip 2b is fastened to the lock grip holders9 by means of fastening means (not shown), such as screws, and a curtainspring 11 is fastened to the middle plate 5 in such a way that itcontacts the lower plate 6 and prevents observation into the lock.

The means arranged to block the displacement of the locking mechanism inthe lock casing 1 consists of circular rings 12 each oriented in planetransverse to the displacement direction of the locking mechanism, andguided in throughgoing slits 4a,5a,6a located in registry to each otherin the three plates 4,5,6. The length and width of these slits somewhatexceed the outer diameter and the axial width, respectively, of therings 12 so as to permit the upward and downward movement of the rings.The slits 5a,6a in the middle plate 5 and the lower plate 6 havecentral, circularly widened portions 5b,6b, in which a guide sleeve 13for a helical spring 14 is located inside each ring 12. Each helicalspring 14 contacts the upper plate 4 (the turns of the helical springhaving a larger diameter than the width of the slit 4a) and, at itslower end, the inside of the ring 12, so that each ring is spring loadeddownwards towards the bottom plate of the lock casing 1, where thelocking tongues 1b secure that the locking mechanism is fixed againstany displacement. In order not to prevent the possibility of the ring 12to move upwards and downwards, each guide sleeve 13 is provided withopposite recesses 13a, 13b in the upper and lower ends. Apart from thepossibility of each ring 12 to move vertically, it has the possibilityto rotate around its axis, which can be used when the punched card shownin FIG. 1 is inserted into the locking mechanism 2 so as to contact therings 12 with its front edge. The guide sleeves 13 and the helicalsprings 14 are, however, kept stationary in their vertically orientedpositions.

When the lock is empty, i.e. before any punched card 3 has beeninserted, the rings 12 are--as mentioned above--pressed down against thebottom of the lock casing and engage with the locking tongues 1b. Thiscondition constitutes the "lower locking position" and is schematicallyshown in FIG. 2 and FIG. 4a. In FIG. 4b the "upper locking position" ofthe lock is shown, wherein a card not adapted to the lock, or any otherflat object 3', has been inserted into the opening 2c of the lock grip2b between the middle plate 5 and the lower plate 6 (and sidewaysbetween the lock grip holders 9). The rings roll up onto the card or theobject 3' (against the action of the springs 13) and are thus insteadpressed upwards against the underside of the upper wall of the lockcasing, where they get into locking engagement with the upper lockingtongues 1a. Because the rings 12 are mutually displaced in the insertingdirection, the locking mechanism 2 is kept fixed even during theinsertion operation itself, since the rings located nearest to theopening 2c will lock at the upper position before the rings furthestaway release their locking engagement in the lower position. The lockcan only be opened by a punched card 3 adapted thereto and havingthrough-going slits 3a, which are located in correspondence to the slits4a,5a,6a in the plates 4,5,6 of the locking mechanism. However, theslits 3a are somewhat shorter than the slits 4a,5a,6a, so that by theaction of the springs 13 the rings 12 are pressed down only partly intothe respective slits 3a, i.e. preferably so far that the rings 12 haveappr. 2/3 of their diameter located above the lower plate 6 whentouching both ends of the slit. Thus, upon insertion of the "right" card3, the rings will firstly roll up onto the upper side of the card (andlock in the upper position as shown in FIG. 4b) and, when the card hasbeen inserted into its final position with the slits 3a in registry withthe slits 4a,5a,6a, the rings roll down partly into the respective slit3a, and reach intermediate, hanging positions, as shown in FIG. 4c, i.e.free from engagement with the upper as well as the lower locking tongues1a and 1b, respectively. In this "releasing position" the entire lockingmechanism 2 including the latch bolt 2a can be displaced by hand ineither direction along the side guides 1d, 1e of the lock casing.

In the illustrated embodiment, the lock is primarily intended to be usedin such doors, shutters, or the like, wherein the lock only needs to beoperated from one side. By means of a symmetric arrangement of theblocking means 12 and a symmetric shape of the lock casing 1 and thelocking mechanism 2, the lock can easily be adjusted to be operated fromboth sides.

By varying the number of the rings 12 and their relative distribution intwo dimensions, as may be desired, a very large number of combinationscan be obtained. In principle (though impractical from the manufacturingand assembling points of view), the rings 12 may have somewhat differentdiameters and the slits 3a in the punched card 3 may be ofcorrespondingly different lengths, whereby the number of combinationscould be increased even more. Also, the fact that the insertion opening2c needs to be only slightly wider than the thickness of the card 3,e.g. appr. 1.5 mm, contributes to the security of the lock, and moreoverthe curtain spring 11 protects the lock from observation through thenarrow opening.

Another advantage of the lock according to the invention is that thelock casing 1 and the parts 4,5,6,9 of the locking mechanism 2 can bemade easily by pressing, bending and punching of relatively thin metalsheets, whereas e.g. the lock grip 2b, the guide sleeves 13 and the carditself can preferably be made of plastic material.

What is claimed is:
 1. A lock including a lock casing, a lockingmechanism displaceable in said lock casing and connected to a latchbolt, and annular blocking means, which are movable transversally to thedisplacement direction of the locking mechanism and resiliently loadedtowards positions blocking the locking mechanism, the blocking meansbeing adapted be brought to releasing positions by insertion of a cardserving as a key and having recesses corresponding to the blockingmeans, said blocking means being entirely guided in the displaceablelocking mechanism and movable between two blocking end positions, inwhich each blocking means is in locking engagement with the lock casing,and said card belonging to the lock having through-going, elongatedslits located and dimensioned to receive arcuate portions of theblocking means, so that upon insertion of the card all the blockingmeans are brought to intermediate positions permitting the displacementof the locking mechanism.
 2. A lock according to claim 1, wherein theblocking means are circular.
 3. A lock according to claim 1, wherein theannular blocking means are guided in slits in parallel, mutuallyconnected plates.
 4. A lock according to claim 3, wherein inside eachannular blocking means a sleeve is disposed to form a guiding means fora helical spring acting on the blocking means.
 5. A lock according toclaim 3 or 4, wherein said locking mechanism substantially consists ofthree plates connected at a distance in parallel to each other, andwherein said card is insertable between two of these plates.
 6. A lockaccording to claim 1, wherein said blocking means are undivided.
 7. Alock according to claim 1, wherein said blocking means are identicalwith respect to each other.
 8. A lock according to claim 1, wherein therelative positions of the slits of the card in the plane thereof arespecific to the lock and correspond to the distribution of the lockingmeans in the locking mechanism.
 9. A lock according to claim 1, whereinsaid intermediate positions are each located at the same distance fromthe respective blocking end positions.